Frame questions

[centralchevyman]

I have a 55 chevy 2nd series truck. I think it is a 3600 which i guess is a 3/4 ton. The vin is j255j004985. I guess my question is im wanting to make it into a shortbed by cutting the frame and was wondering if people use 3/4 ton frames to do that? Or do i just need a new frame?

[dwcsr]

I would use the original frame. Its thicker than a 1/2 ton. making a 3/4 ton short makes it ride very rough unless you swap out the springs

[centralchevyman]

I'm going to be using a ifs up front and a 4 link in the back. Is it a bad Idea to use a 3/4 ton frame still
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[_Ogre]

The problem with the heavy frame is that no after market parts are guaranteed to fit.
MustII ifs and any 4 link is a crap shoot to whether it will fit.
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[BIG CHEVY 3600]

Originally Posted by _Ogre

The problem with the heavy frame is that no after market parts are guaranteed to fit.
MustII ifs and any 4 link is a crap shoot to whether it will fit.
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I don't know about the 55 but the only issue I had with my 51 3600 was with the rear sway bar. I had to use some creative installation techniques but I got it to fit. The only difference between the 3100 and the 3600 is the width of the frame at the rear. The 3100 is 11.5" wider than the 3600. My IFS is a Heidts Superide and fits just fine; my rear is a 1980 Camaro and it fits just fine.

[mr48chev]

I don't think you will have an issue and I've never put a caliper on a Taskforce half of 3/4 ton truck but I'd bet dollars to donuts that the frames are the same and the only difference is the springs and axles.
I've seen more than one Task Force truck that the owner pulled the 3/4 ton suspension and axles out of and put 1/2 ton under it to turn it into a 1/2 ton
.
It's like the old nonsense that went around for years that GMC's had heavier frames than Chevys did and that carried on clear up into the 70's when they were going down the assembly line one behind the other.

One of the guys over on the 67/72 page posted a diagram for shortening the frame without loosing any strength Instead of a butt weld you cut the rails so that they overlap.


The measurements won't jive for your truck but the concept is the same.

On the AD trucks the 1/2 ton frame tapers out and gets wider at the back while the 3/4 ton frame runs pretty well straight back and a guy could run into issues there with rear suspension pieces designed for a 1/2 ton. The Task force frames on either half or 3/4 ton run pretty well straight back from the back of the cab on either 1/2 or 3/4 ton trucks.

[centralchevyman]

Thanks everyone for the help. Greatly appreciated

[dwcsr]

Frame thicknesses for 1954 to 1959 Chevy.

3100 9/64"

32-3600 3/16"

3800 7/32"

This is from the Chevrolet Truck Data Books. I don't have past 54 so I can't say for sure but have no reason to believe its different back to 47.2. GMC did have a different frame up to 59 whether it was thicker or not I can't say but is was definitely different than Chevy.

GMC came off a Pontiac line not behind a Chevy on the same line. Maybe in 72 they did but not prior to 59. There wasn't anything that was the same even in the same years. The body panels were different enough to require their on assembly line. They did have a lot of similar drive line parts but cabs, fenders, trim , engines, radiators, grilles were all different than Chevy.